Truck air supply parts at Truckstop Group
The pneumatic system on an HGV is not just a convenience feature — it directly powers the braking system, suspension, gear selection and auxiliary equipment. A slow pressure build-up, excessive moisture discharge from the air dryer, or an air processing unit running outside specification are faults that need attention before they become safety issues. Most air supply failures follow a predictable pattern: a worn compressor reduces output pressure, which stresses the dryer cartridge, which saturates faster and allows moisture into the downstream system.
Our air supply range covers each stage of the system. Air compressors generate the compressed air that feeds the reservoirs; correct output pressure is critical for the braking system to build to the required threshold within the allowable time at startup. Air dryer cartridges remove water vapour from the compressed air before it reaches the valves and chambers — a saturated cartridge allows moisture through, which causes freezing in cold weather and corrosion of internal valve components. Desiccant cartridges serve the same moisture-removal function. Air processing units integrate filtration, pressure regulation and moisture removal into a single assembly.
Most air dryer cartridges should be replaced annually or at the manufacturer's service interval. On vehicles operating in damp or cold climates, more frequent replacement is worthwhile. Where a compressor is being replaced, inspecting the dryer at the same time is good practice — a failed compressor will often have already sent contaminated air into the dryer. Call our team with your chassis number for part identification.
Frequently asked questions
How often should an HGV air dryer cartridge be replaced?
Most manufacturers recommend annual replacement or at the standard service interval, whichever comes first. Vehicles operating in consistently damp or cold conditions — where the dryer is working harder to remove moisture — may benefit from replacement every six months.
What are the signs of a failing air compressor on an HGV?
Slow pressure build-up at startup, dashboard warnings for low air pressure, excessive oil contamination in the air system and audible changes in compressor output are all indicators of a failing unit. A diagnostic scan will confirm whether the fault is in the compressor circuit or elsewhere in the system.
What is the difference between an air dryer cartridge and a desiccant cartridge?
Both remove moisture from compressed air, but they refer to variants used on different air dryer designs. Some air dryers use a self-contained cartridge assembly; others use a replaceable desiccant cartridge within the dryer housing. The correct part depends on the dryer unit fitted to the vehicle. Cross-reference the dryer make and model before ordering.
